Six Methods for Oracle generation Sequence

Six methods for generating sequences in Oracle [SQL] Method 1: sys @ ORCL> select level from dual connect by level <= 5; LEVEL ---------- 1 2 3 4 5 Method 2: sys @ ORCL> select rownum from dba_objects where rownum <= 5; ROWNUM ---------- 1 2 3 4 5 method 3: sys @ ORCL> select to_number (column_value) n from xmltable ('1 to 5'); N ---------- 1 2 3 4 5 Method 4: select n from (select 1 v from dual) model dimension by (v) measures (v n) rules (n [for v from 2 to 5 increment 1] = n [cv (v)-1] + 1) sys @ ORCL>/N ---------- 1 2 3 4 5 Method 5: with t (n) as (select 1 from dual union all select n + 1 from t where n <5) select n from t sys @ ORCL>/N ---------- 1 2 3 4 5 Method 6: create or replace function generator (n pls_integer) return sys. odcinumberlist pipelined is m pls_integer: = trunc (n/10); r pls_integer: = n-10 * m; begin for I in 1 .. m loop pipe row (null ); pipe row (null); end loop; for I in 1 .. r loop pipe row (null); end loop; end;/alter function generator compile plsql_code_type = native; sys @ ORCL> select * from table (generator (5 )); N ---------- 1 2 3 4 5